|
  |
| |
|
| |
Developmental
Abnormalities of Glycosylphosphatidylinositol-AnchorEmbryos Revealed by
Cre/loxP System |
|
|
Masami Nozaki,
Kazuhito Ohishi, Naoko Yamada, Taroh Kinoshita, Andras Nagy, and Junji Takeda
|
| |
|
| |
Departments
of Molecular Embryology (MN, NY) and Immunoregulation (KO, TK, JT), Research
Institute for Microbial Diseases, Osaka University, Osaka, Japan; and Mount
Sinai Hospital (AN), Samuel Lunenfeld Research Institute, Toronto, Ontario,
Canada |
| |
|
| |
One mode used to link membrane
proteins to a cell membrane is by means of a special glycolipid anchor termed
glycosylphosphatidylinositol (GPI). Pig-a, an X-linked gene, is involved
in the first step of GPI-anchor biosynthesis. Disruption of this gene causes
cessation of GPI biosynthesis on the endoplasmic reticulum, thereby leading
to the absence of GPI-anchored proteins on the cell surface. We have previously
reported that mice with high chimerism was never obtained from Pig-a
disrupted ES cells, suggesting that GPI-anchored protein(s) may have
important roles for mouse development such that the absence of GPI-anchored
proteins causes a lethal effect to mice. In this study, this lethal effect
has been investigated by using a conditional approach to "knockout"
the Pig-a gene. For this, mice harboring a Pig-a gene flanked
by two loxP sites (Pig-a flox) were
mated with hCMV-Cre transgenic mice, which express Cre recombinase
before implantation. The allele disruptions were identified by PCR analysis
of embryo yolk sac DNA. Embryos harboring a complete disruption of Pig-a
gene ceased to develop beyond the ninth day of gestation. Female embryos
in which one Pig-a allele was disrupted by Cre such that only
half of the cells in the embryo proper did not express GPI-anchored proteins
due to random X inactivation developed until 19 days post coitum (dpc),
but showed abnormal phenotypes such as insufficient closure of neural tube
and cleft palate. These data further highlight the importance of GPI-anchored
proteins during mouse embryonic development. (Lab Invest 1999 79:293-299). |
| |
|
| |
 |
